1,122 research outputs found
A single baseline ultrasound assessment of fibroid presence and size is strongly predictive of future uterine procedure: 8-year follow-up of randomly sampled premenopausal women aged 35-49 years.
STUDY QUESTION: How well can a single baseline ultrasound assessment of fibroid burden (presence or absence of fibroids and size of largest, if present) predict future probability of having a major uterine procedure?
SUMMARY ANSWER: During an 8-year follow-up period, the risk of having a major uterine procedure was 2% for those without fibroids and increased with fibroid size for those with fibroids, reaching 47% for those with fibroids ≥4 cm in diameter at baseline.
WHAT IS KNOWN ALREADY: Uterine fibroids are a leading indication for hysterectomy. However, when fibroids are found, there are few available data to help clinicians advise patients about disease progression.
STUDY DESIGN, SIZE, DURATION: Women who were 35-49 years old were randomly selected from the membership of a large urban health plan; 80% of those determined to be eligible were enrolled and screened with ultrasound for fibroids ≥0.5 cm in diameter. African-American and white premenopausal participants who responded to at least one follow-up interview (N = 964, 85% of those eligible) constituted the study cohort. During follow-up (5822 person-years), participants self-reported any major uterine procedure (67% hysterectomies). Life-table analyses and Cox regression (with censoring for menopause) were used to estimate the risk of having a uterine procedure for women with no fibroids, small (diameter), medium (2-3.9 cm), and large fibroids (≥4 cm). Differences between African-American and white women, importance of a clinical diagnosis of fibroids prior to study enrollment, and the impact of submucosal fibroids on risk were investigated.
PARTICIPANTS/MATERIALS, SETTING, METHODS: There was a greater loss to follow-up for African-Americans than whites (19 versus 11%). For those with follow-up data, 64% had fibroids at baseline, 33% of whom had had a prior diagnosis. Of those with fibroids, 27% had small fibroids (diameter), 46% had medium (largest fibroid 2-3.9 cm in diameter), and 27% had large fibroids (largest ≥4 cm in diameter). Twenty-one percent had at least one submucosal fibroid.
MAIN RESULTS AND THE ROLE OF CHANCE: Major uterine procedures were reported by 115 women during follow-up. The estimated risk of having a procedure in any given year of follow-up for those with fibroids compared with those without fibroids increased markedly with fibroid-size category (from 4-fold, confidence interval (CI) (1.4-11.1) for the small fibroids to 10-fold, CI (4.4-24.8) for the medium fibroids, to 27-fold, CI (11.5-65.2) for the large fibroids). This influence of fibroid size on risk did not differ between African-Americans and whites (P-value for interaction = 0.88). Once fibroid size at enrollment was accounted for, having a prior diagnosis at the time of ultrasound screening was not predictive of having a procedure. Exclusion of women with a submucosal fibroid had little influence on the results. The 8-year risk of a procedure based on lifetable analyses was 2% for women with no fibroids, 8, 23, and 47%, respectively, for women who had small, medium or large fibroids at enrollment. Given the strong association of fibroid size with subsequent risk of a procedure, these findings are unlikely to be due to chance.
LIMITATIONS, REASONS FOR CAUTION: Despite a large sample size, the number of women having procedures during follow-up was relatively small. Thus, covariates such as BMI, which were not important in our analyses, may have associations that were too small to detect with our sample size. Another limitation is that the medical procedures were self-reported. However, we attempted to retrieve medical records when participants agreed, and 77% of the total procedures reported were verified. Our findings are likely to be generalizable to other African-American and white premenopausal women in their late 30s and 40s, but other ethnic groups have not been studied.
WIDER IMPLICATIONS OF THE FINDINGS: Though further studies are needed to confirm and extend the results, our findings provide an initial estimate of disease progression that will be helpful to clinicians and their patients.
STUDY FUNDING/COMPETING INTERESTS: Funding came from the Intramural Research Program of the National Institute of Environmental Health Sciences and the Office of Research on Minority Health, National Institutes of Health, Health and Human Services (IRB #OH95-E-N048). The authors have no conflicts of interest.
TRIAL REGISTRATION NUMBER: Not applicable
Modeling the Extragalactic Background Light and the Cosmic Star Formation History
We present an updated model for the extragalactic background light (EBL) from
stars and dust, over wavelengths approximately 0.1 to 1000 m. This model
uses accurate theoretical stellar spectra, and tracks the evolution of star
formation, stellar mass density, metallicity, and interstellar dust extinction
and emission in the universe with redshift. Dust emission components are
treated self-consistently, with stellar light absorbed by dust reradiated in
the infrared as three blackbody components. We fit our model, with free
parameters associated with star formation rate and dust extinction and
emission, to a wide variety of data: luminosity density, stellar mass density,
and dust extinction data from galaxy surveys; and -ray absorption
optical depth data from -ray telescopes. Our results strongly
constraint the star formation rate density and dust photon escape fraction of
the universe out to redshift , about 90% of the history of the universe.
We find our model result is, in some cases, below lower limits on the EBL
intensity, and below some low- -ray absorption measurements.Comment: 23 pages, 12 figures, 3 tables. Accepted for publication in AAS
journal
Network-based optimization techniques for wind farm location decisions
2018 The Author(s) 2018. Published by Higher Education Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0)This study aims to find appropriate locations for wind farms that can maximize the overall energy output while controlling the effects of wind speed variability. High wind speeds are required to obtain the maximum possible power output of a wind farm. However, balancing the wind energy supplies over time by selecting diverse locations is necessary. These issues are addressed using network-based models. Hence, actual wind speed data are utilized to demonstrate the advantages of the proposed approach.We would like to thank the anonymous reviewers for their insightful comments. The partial support of the Ministny of Education of Bolivia Texas A&M Energy Institute is also gratefully acknowledged
Critical statistics in a power-law random banded matrix ensemble
We investigate the statistical properties of the eigenvalues and eigenvectors
in a random matrix ensemble with . It is known that
this model shows a localization-delocalization transition (LDT) as a function
of the parameter . The model is critical at and the eigenstates
are multifractals. Based on numerical simulations we demonstrate that the
spectral statistics at criticality differs from semi-Poisson statistics which
is expected to be a general feature of systems exhibiting a LDT or `weak
chaos'.Comment: 4 pages in PS including 5 figure
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Dialectic tensions in the financial markets: a longitudinal study of pre- and post-crisis regulatory technology
This article presents the findings from a longitudinal research study on regulatory technology in the UK financial services industry. The financial crisis with serious corporate and mutual fund scandals raised the profile of
compliance as governmental bodies, institutional and private investors introduced a ‘tsunami’ of financial regulations. Adopting a multi-level analysis, this study examines how regulatory technology was used by financial firms to meet their compliance obligations, pre- and post-crisis. Empirical data collected over 12 years examine the deployment of
an investment management system in eight financial firms. Interviews with public regulatory bodies, financial
institutions and technology providers reveal a culture of compliance with increased transparency, surveillance and
accountability. Findings show that dialectic tensions arise as the pursuit of transparency, surveillance and
accountability in compliance mandates is simultaneously rationalized, facilitated and obscured by regulatory
technology. Responding to these challenges, regulatory bodies continue to impose revised compliance mandates on
financial firms to force them to adapt their financial technologies in an ever-changing multi-jurisdictional regulatory landscape
A blood-based metabolomics test to distinguish relapsing–remitting and secondary progressive multiple sclerosis: addressing practical considerations for clinical application
The transition from relapsing–remitting multiple sclerosis (RRMS) to secondary progressive MS (SPMS) represents a huge clinical challenge. We previously demonstrated that serum metabolomics could distinguish RRMS from SPMS with high diagnostic accuracy. As differing sample-handling protocols can affect the blood metabolite profile, it is vital to understand which factors may influence the accuracy of this metabolomics-based test in a clinical setting. Herein, we aim to further validate the high accuracy of this metabolomics test and to determine if this is maintained in a ‘real-life’ clinical environment. Blood from 31 RRMS and 28 SPMS patients was subjected to different sample-handling protocols representing variations encountered in clinics. The effect of freeze–thaw cycles (0 or 1) and time to erythrocyte removal (30, 120, or 240 min) on the accuracy of the test was investigated. For test development, samples from the optimised protocol (30 min standing time, 0 freeze–thaw) were used, resulting in high diagnostic accuracy (mean ± SD, 91.0 ± 3.0%). This test remained able to discriminate RRMS and SPMS samples that had experienced additional freeze–thaw, and increased standing times of 120 and 240 min with accuracies ranging from 85.5 to 88.0%, because the top discriminatory metabolite biomarkers from the optimised protocol remained discriminatory between RRMS and SPMS despite these sample-handling variations. In conclusion, while strict sample-handling is essential for the development of metabolomics-based blood tests, the results confirmed that the RRMS vs. SPMS test is resistant to sample-handling variations and can distinguish these two MS stages in the clinics
The Self stepping into the shoes of the Other: Understanding and developing self-perceptions of empathy among prospective physical education teachers through a special school placement
Teachers who demonstrate a high degree of empathy are said to have more positive attitudes towards pupils with disabilities. Therefore, this article sought to explore the influence of a special school placement on prospective teachers’ self-perceptions of empathy. Thirty-two final year undergraduate students participated in focus group interviews and were selected because they aspired to be a physical education teacher and had attended a placement in a special school. Interview transcripts were analysed and the following themes constructed: Stepping into the shoes of the Other; Frustrated ‘for’ not ‘with’ pupils with disabilities; Empathy for planning inclusive lessons and ‘reading’ pupil body language; and Knowing when not to show empathy. All prospective teachers felt that: (a) they could empathise with pupils with disabilities; (b) situated learning experiences within the placement enabled them to reflect on the ways in which their empathy influences their teaching now and could continue to do so in the future; and (c) it was important that teachers demonstrated empathy. Thus, it is recommended that all prospective teachers gain some experience teaching in special schools. Our research also warns against teachers claiming the last, conclusive word about who children with disabilities are, what they think, how they feel and what they want, in myriad contexts and situations
Moving beyond methodising theory in preparing for the profession
For those preparing for outdoor education and related professions, formal theory has an important role to play in terms of informing professional practice and understandings of teaching-learning dynamics. Despite this, surprisingly little is understood about how pre-service outdoor educators (POEs) view and engage with it in their preparation courses. Drawing on findings of a case study in an Australian outdoor education teacher education (OETE) course, this article explores POE theory engagement focussing on a problematic tendency to methodise formal theory, that is, to treat theories as formula for action. The authors argue that this tendency is concerning because it ignores the complexity and problematic nature of both theory-practice relationships and outdoor education pedagogy. The discussion highlights contributing factors and implications for OETE, especially with respect to enabling aspiring outdoor educators in tertiary courses to move beyond methodising theory as they enter the outdoor profession
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